Occlusive vascular disease is a common ailment in people resulting in enormous costs to the health care especially with the ‘Graying of America’ due to the baby boomers of the 50's. The common procedure of dilatation of these occluded vessels of the body has been studied for several years and many techniques (devices and methods) have been studied and practiced. One of the more common techniques is one referred to as balloon angioplasty or Percutaneous Transluminal Angioplasty (PTA). PTA is the most common treatment of atherosclerotic plaque deposition. However, this PTA has significant drawbacks; some of which are the cost of the catheter and the potential for the stenotic vessel to ‘recoil’ or narrow back down after the procedure. Hence scaffolds (stents or stent-grafts) have been designed that stay in place to keep the vessel ‘propped open’ after dilatation. Other significant design changes have occurred with PTA such as the use of drugs pre, during and post dilation. Balloons have been designed with permeable membranes to aid with this delivery. Further, the balloons have been designed with imperfections in the surface of the balloon that aid in breaking up the plaque matrix during dilation (tiny cutters for example have been impregnated into the exterior wall of the balloon). Further energy dispersal systems have been employed to deliver energy to the site pre, during or post therapy (e.g. radiation, electrical stimulation, RF, etc.). Even further, extravagant perfusion systems have been developed with the dilatation systems so that blood can flow during the therapy. All of these proposed ‘enhancements’ add significantly to the cost and complexity of the dilation or stent device. The present invention allows all of these enhancements to occur with an overall reduction in the manufacturing resources required for the device since one device/catheter is required as opposed to two or more. Even more important, is the time efficiencies created during the procedure by obviating the need to exchange the devices/catheters to perform the acts which may include angioplasty, stent deployment, and drug delivery. Safety to the patient is enhanced, as well, by obviating the time consuming exchanges and diminishing the time of the procedure.
Also, despite the evolution of a variety of mechanical techniques and adjunctive therapies, approximately 30–45% of patients treated with balloon angioplasty will develop a recurrent stenosis within six months. Stenting of the lesion will decrease the re-stenosis rate to 20–30%, although with additional cost and risks. The cost of treating patients with re-stenosis which require another revascularization procedure or additional therapy and has been estimated to cost 2500 lives and $4 billion. Re-stenosis is a complex process, which is due to some combination of suboptimal results, acute mechanical recoil, thrombosis and platelet deposition, smooth muscle proliferation, extracellular matrix production, and geometric remodeling as well as other reasons not reported here. Because of the improvement in the re-stenosis rate with intraluminal stents, it is likely that stenting prevents the mechanical events which contribute to re-stenosis, i.e., suboptimal results, acute mechanical recoil, and geometric remodeling. However, stenting has been shown to accelerate or incite smooth muscle proliferation, thrombosis and platelet deposition, and matrix production. These events may be grouped together and referred to as neointimal hyperplasia. Exuberant neointimal hyperplasia may lead to stenosis within a stent, referred to as in-stent re-stenosis. Therefore, stents may improve the re-stenosis rate, but at a significant financial cost, potential risk to the patient, and a possibility of developing in-stent stenosis. Hence, a novel invention that allows safer, less expensive and more efficacious dilatation and stent deployment is described in the present invention.
As stated, stenting is not the cure all. Moreover, pharmacological therapy has not been shown efficacious in significantly reducing neointimal hyperplasia, for several different reasons. One reason is related to the systemic intolerances of doses required to achieve local beneficial effects within the arterial wall. A local drug delivery device which would deliver higher drug concentration to the target while avoiding systemic toxicity's or side effects would be advantageous. In fact there are several patented local drug delivery devices, including balloon catheters, coated stents, and even needle catheters. However, most are plagued with the rather uniform problem of low transfer efficiency, rapid washout/poor retention, and the potential of additional vessel injury. Most also require insertion of a separate and specialized catheter separate from the angioplasty balloon catheter, which is a time consuming, costly, and potentially a risky maneuver.
There are many techniques and devices known in the art for removing blockages, repairing occlusions and otherwise preventing or treating disease in the passageways of the human body. Further, many approaches exist to treat the synthetic/tissue interface that exists when using medical devices and implants in the body. However, there is a continuing need for improved devices to meet at least the following objectives.
The first objective is to reduce cost. This is particularly important in recent years where it is clear for safety and sanitary reasons that these will be single use devices. A device, even though it performs a function in some improved manner, will not be widely used if it is considerably more costly than the alternatives available.
A second objective is to provide a device that is simple to use and in a very real sense simple to understand. This will encourage its adoption and use by medical personnel. It will also tend to keep cost low.
The third objective is to provide a device that entails a procedure with which the medical profession is familiar so that the skills that have been learned from previous experience will continue to have applicability.
A fourth objective relates to the effectiveness and thoroughness with which the blockage is removed. It is important that a maximum amount of the blockage be removed; recognizing that no device is likely to provide one hundred percent removal.
A fifth objective concerns safety; a matter which is often so critical as to trump the other considerations. It is important to avoid tissue trauma. In many circumstances, it is critically important to avoid breaking up a blockage in a fashion that leads to flushing elements of the blockage throughout the body involved.
There are trade-offs in design considerations to achieve the above five interrelated objectives. Extreme simplicity and a very simple procedure might over compromise safety. Addressing all of these considerations calls for some trade-off between the objectives.
Accordingly, a major object of this invention is to provide an improved device for treatment or prevention of disease of a body passageway, which achieves the objectives of, reduced cost, enhanced simplicity, a standard procedure, high effectiveness and a high degree of safety. Most particularly, it is an object of the present invention to achieve these objectives with an enhanced trade-off value for the combined objectives.